fix: add contract, restrict imports
fix: add contract, restrict imports

Bugfry/exercism,Bugfry/exercism,Bugfry/exercises,Bugfry/exercism,Bugfry/exercism,Bugfry/exercises,Bugfry/exercism,Bugfry/exercism,Bugfry/exercises,Bugfry/exercises,Bugfry/exercises,Bugfry/exercises